Processing apparatus and cleaning method

ABSTRACT

Provided is a parallel-plate-type processing apparatus ( 10 ), which performs plasma CVD and includes a chamber ( 11 ) to be cleaned. To perform cleaning of the chamber ( 11 ), plasma of a gas including fluorine is generated outside the chamber ( 11 ), and supplied into the chamber ( 11 ). During the cleaning, an RF power is applied to electrode plates ( 12, 17 ) inside the chamber ( 11 ).

TECHNICAL FIELD

[0001] The present invention relates to a processing apparatus and acleaning method in which an efficient cleaning is possible.

BACKGROUND ART

[0002] Various CVD (Chemical Vapor Deposition) apparatuses are used formanufacturing electronic devices, such as semiconductor devices, LCD(Liquid Crystal Display) devices, etc. Plasma CVD apparatuses are widelyused for forming high quality films.

[0003] The plasma CVD apparatus forms a film on a semiconductor wafercontained inside a decompressed chamber, using a CVD method. The CVDmethod employs a gas phase reaction. Thus, films are formed only on thesurface of the wafers, but on the surface (internal wall, etc.) of achamber member. Thus formed films cause particles to be generated,thereby lowering the yield of the products. In such circumstances, it isnecessary to regularly clean the inside of the chamber, to remove thefilms formed on the chamber member.

[0004] A well-known method for cleaning the inside of the chamber is anin-situ plasma cleaning method, wherein a cleaning gas is introducedinto the chamber, and plasma is generated from a gas inside the chamber.However, plasma is generated inside the chamber, so that the chambermember is likely to be deteriorated.

[0005] A remote plasma cleaning method has been proposed. In this remoteplasma cleaning method, plasma of a cleaning gas is generated outsidethe chamber, and the generated plasma is introduced into the chamber soas to clean the inside of the chamber. Using this remote plasma cleaningmethod, the chamber member is unlikely to be deteriorated. Such a remoteplasma cleaning method is disclosed in Unexamined Japanese PatentApplication KOKAI Publication No. H9-69504 (U.S. Priority No.08/278605).

[0006] A problem in the remote plasma cleaning method is that itrequires a relatively long period of time for the cleaning. In theremote plasma cleaning method, the plasma gas is introduced from one ortwo point(s) into the chamber, so that the inside of the chamber is notevenly cleaned. Using the remote plasma cleaning method, it takes a longtime for cleaning entirely the inside of the chamber, resulting that apart of the chamber member is deteriorated due to the excessivecleaning.

[0007] Accordingly, in the conventional CVD apparatus, the cleaning ofthe chamber is not performed with high efficiency, and a high yield ofthe products is not sufficiently be obtained.

DISCLOSURE OF INVENTION

[0008] The present invention has been made in consideration of theabove. It is accordingly an object of the present invention to provide aprocessing apparatus and a cleaning method by which a cleaning with highefficiency is possible.

[0009] In order to achieve the above objects, according to the firstaspect of the present invention, there is provided a processingapparatus (10) comprising: a chamber (11); a gas source (SA) forsupplying a gas for cleaning inside of said chamber (11); a gas line(L1) for introducing the gas supplied from said gas source (SA) intosaid chamber (11); an activator (27) which is prepared in said gas line(L1) and activates the gas supplied from said gas source (SA); and atleast three gas inlets (28) which are provided at a side wall of saidchamber (11) and connected to said gas line (L1).

[0010] In order to achieve the above objects, according to the secondaspect of the present invention, there is provided a method for cleaninga processing apparatus (10) including two electrodes (12, 17) in achamber (11), said method comprising the steps of: introducing a gas forcleaning into said chamber (11); and applying an RF power to each of thetwo electrodes (12, 17), thereby activating the gas for cleaning.

BRIEF DESCRIPTION OF DRAWINGS

[0011]FIG. 1 is a diagram showing the structure of a processingapparatus according to the first embodiment of the present invention.

[0012]FIG. 2 is a diagram showing cleaning results obtained using theprocessing apparatus of FIG. 1.

[0013]FIG. 3 is a diagram showing cleaning results obtained using theprocessing apparatus of FIG. 1.

[0014]FIG. 4 is a diagram showing the structure of a processingapparatus according to the second embodiment of the present invention.

[0015]FIG. 5 is a cross sectional view showing the processing apparatusof FIG. 4.

[0016]FIG. 6 is a diagram showing cleaning results obtained using theprocessing apparatus of FIG. 4.

[0017]FIG. 7 is a diagram showing cleaning results obtained using theprocessing apparatus of FIG. 4.

[0018]FIG. 8 is a diagram showing the structure of a processingapparatus according to the third embodiment of the present invention.

[0019]FIG. 9 is a diagram showing cleaning results obtained using theprocessing apparatus of FIG. 8.

[0020]FIG. 10 is a diagram showing a processing apparatus as acomparative example.

[0021]FIG. 11 is a diagram showing a lid member included in a processingapparatus according to the fourth embodiment.

[0022]FIG. 12 is a diagram showing cleaning results obtained using theprocessing apparatus according to the fourth embodiment.

[0023]FIG. 13 is a diagram showing a modification of the lid memberincluded in the processing apparatus according to the fourth embodiment.

[0024]FIG. 14 is a diagram showing further cleaning results obtainedusing the processing apparatus of the fourth embodiment.

[0025]FIG. 15 is a diagram showing the lid member as a comparativeexample as a comparative example.

[0026]FIG. 16 is a diagram showing the structure of a processingapparatus according to the fifth embodiment.

[0027]FIG. 17 is a diagram showing cleaning results obtained using theprocessing apparatus of the fifth embodiment.

[0028]FIG. 18 is a diagram showing another structure of the processingapparatus of the fifth embodiment.

[0029]FIG. 19 is a diagram showing another structure of the processingapparatus of the fifth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0030] A processing apparatus according to the first embodiment of thepresent invention will now be explained with reference to the accompanydrawings.

[0031] The processing apparatus according to the first embodimentincludes a chamber. In this chamber, SiOF films are formed respectivelyon semiconductor wafers (hereinafter referred to as a wafer W) using aplasma CVD method, with a process gas containing SiH₄, SiF₄ and O₂. TheSiOF film remaining in the chamber after the formation is removedtherefrom, using a cleaning gas containing NF₃.

First Embodiment

[0032]FIG. 1 shows a cross sectional view of a processing apparatus 10according to the first embodiment of the present invention. As shown inFIG. 1, the processing apparatus 10 comprises a chamber 1, a cleaninggas line L1, a process gas line L2, an exhaust line L3, and a systemcontroller 100.

[0033] The cleaning gas line L1 connects the chamber 11 to an NF₃ sourceSA, serving as a cleaning gas source, and also to an Ar source SB,serving as a carrier gas source. The NF₃ source SA and Ar source SB areconnected to the cleaning gas line L1, respectively through mass-flowcontrollers MA and MB, and also through valves VA and VB. Those lines,for connecting the NF₃ source SA and Ar source SB, and chamber 11 are,connected on vent parts of the valves VA and VB so as to be formed intoa single line. In this structure, NF₃ and Ar are mixed at apredetermined ratio by the controllers MA and MB and valves VA and VB,and supplied to the chamber 1.

[0034] The process gas line L2 connects chamber 11 to an SiF₄ source SC,an SiH₄ source SD, an O₂ source SE, and to an Ar source SF. The SiF₄source SC, SiH₄ source SD, O₂ source SE, and Ar source SF are connectedto the process gas line L2 respectively through mass-flow controllersMC, MD, ME, and MF, and also through valves VC, VD, VE, and VF. Thoselines for connecting the SiF₄ source SC, SiH₄ source SD, O₂ source SEand Ar source SF, and chamber 11 are converged on the vent parts of thevalves VC, VD, VE, and VF, so as to be formed into a single line. Inthis structure, SiF₄, SiH₄, O₂ and Ar are mixed at a predetermined ratioby the mass-flow controllers MC, MD, ME, and MF and also the valves VD,VD, VE, and VF, and supplied to the chamber 11.

[0035] The chamber 11 is a reactive chamber which can be decompressedinto a vacuum state. The chamber 11 is formed approximately in acylindrical shape, made of aluminum, etc., and is grounded.

[0036] Provided on the side wall of the chamber 11 is a gate forcarrying in and out wafers W to and from the chamber 11 through a gatevalve. A susceptor 12 is provided in the middle of the chamber 11.

[0037] The susceptor 12 made from a conductor such as aluminum, forexample, and formed almost in a cylindrical shape. Mounted on the uppersurface of the susceptor 12 is a wafer W and an electrostatic chuckwhich electrostatically absorbs the wafer W so as to fix the wafer Wthereonto.

[0038] A focus ring 13 is provided on the upper surface of the susceptor12. In this structure, plasma can effectively contact the wafer Wmounted on the susceptor 12. There is provided in the susceptor 12 alift pin which can go up and down for receiving and providing the wafer.

[0039] A chiller room 14 is provided in the susceptor 12. A chillerflows into each of the chiller room 14 through a pipe. The temperatureof the susceptor 12 and wafer W on the susceptor 12 is adjusted by thechiller. Note that, a chiller means a temperature controlling mediumherein.

[0040] The susceptor 12 is connected to the first RF power source 16through the first matching box 15. One end of the first RF power source16 is grounded; so that an RF voltage can be applied to the susceptor12.

[0041] An electrode plate 17 is tightened up to an electrode supporter18 at the ceiling of the chamber 11. The electrode plate 17 faces and isparallel to the susceptor 12. The electrode plate 17 is formed from aconductor such as aluminum. A Shield ring 19, for protecting thesections of the electrode plate 17 which are fixed to the electrodesupporter 18, is provided beneath the peripheral of the electrode plate17.

[0042] The electrode plate 17 is connected to the second RF power source21 through the second matching box 20. One end of the second RF powersource 21 is grounded, so that an RF voltage is applied to the electrodeplate 17. Accordingly, the electrode plate 17 and susceptor 12 functionrespectively as an upper electrode and lower electrode of aparallel-plate-type plasma CVD apparatus.

[0043] A cleaning-gas inlet pipe 22 and a process-gas inlet pipe 23 areprovided on the upper section of the chamber 11. The cleaning-gas inletpipe 22 is connected to the cleaning gas line L1, so that a cleaning gasis introduced into the chamber 11 through the cleaning gas inlet pipe22. The process-gas inlet pipe 23 is connected to the process gas lineL2, so that a process gas is introduced into the chamber 11 through theprocess-gas inlet pipe 23.

[0044] The electrode supporter 18 includes a diffusing portion such as ahollow, for diffusing the process gas. The electrode plate 17 has aplurality of holes 17 a throughout the electrode plate 17. The cleaninggas and process gas which are diffused by the diffusing portion are sentto the wafer W through the holes 17 a of the electrode plate 17.

[0045] An annular vent 24 is provided at the bottom of the chamber 11.The vent 24 is connected to the exhaust line L3. The exhaust line L3 isconnected to a TMP (Turbo Molecular Pump) 25. A dry pump is provideddownstream of the TMP 25, so that the chamber 11 can be decompressed soas to be in a vacuum state. An APC (Automatic Pressure Controller) 26 isprovided between the TMP 25 and the chamber 11. The chamber 11 iscontrolled to be in a predetermined pressure level by the APC 26.

[0046] The system controller 11 controls the processing apparatus 10totally, including a film formation process and a cleaning process whichare carried out inside the processing apparatus 10.

[0047] The film formation process and cleaning process carried out bythe processing apparatus 10 of the first embodiment will now beexplained with reference to FIG. 1. Those procedures included in theabove processes will be explained below for description purposes only,and the present invention is not limited to them.

[0048] The wafer W is carried into the chamber 11, and put on thesusceptor 12. The wafer W is fixed thereon by the electrostatic chuck.The system controller 100 opens the valve VE so as to supply O₂, andapplies an RF power to the upper electrode (the electrode plate 17).Subsequently, the system controller 100 opens the valves VC, VD, and VF,supplies the chamber 11 with SiF₄, SiH₄, and Ar, and applies a voltageto the lower electrode (the susceptor 12). From this, plasma of the gasis generated, and the SiOF film formation reaction undergoes on and overthe surface of the wafer W.

[0049] After the SiOF film having a predetermined thickness is formed onthe wafer W, or after a predetermined time, the system controller 100stops applying an RF power to the lower electrode, and closes the valvesVC, VD, and VF, so as to stop supplying the chamber 11 with SiF₄, SiH₄,and Ar. After this, the electrostatic chuck is released. The systemcontroller 100 closes the valve VE so as to stop supplying O₂ andapplying an RF power to the upper electrode. Then, the wafer W iscarried out from the chamber 11, and hence completing the film formationprocess.

[0050] After the above-described film formation process is done for apredetermined number of wafers, the system controller 100 startscleaning the chamber 11. A dummy wafer W for cleaning is carried intothe chamber 11, and put on the susceptor 12. The dummy wafer W put onthe susceptor 12 is fixed by the electrostatic chuck. Then, the systemcontroller 100 opens the valves VA and VB, and supplies the chamber 11with NF₃ and Ar.

[0051] A cleaning gas is supplied into the chamber 11 at a ratio ofNF₃/Ar=500/500 (sccm/sccm). The pressure inside the chamber 11 is set to13Pa by the APC 26.

[0052] After the cleaning gas is thus supplied, the system controller100 start applying an RF power to the upper and lower electrodes, so asto begin the cleaning. Note that applied to the upper electrode is an RFpower of approximately 1500W, and applied to the lower electrode is anRF power of approximately 500W. Upon application of the RF power to thecleaning gas, plasma of the gas especially containing fluorine radicalis generated. An NF₃ plasma (containing, mainly, fluorine radical)reacts with SiOF deposited inside the chamber 1, as explained in thefollowing formula. As shown in the following formula, SiOF is decomposedby NF₃, so as to be exhausted as a gas of, for example, SiH₄, etc.

SiOF+NF₃→SiF₄↑+1/2O₂↑+1/2N₂↑

[0053] The system controller 100 monitors a light emission of the plasmagenerated (for example, of oxygen) during the cleaning process, anddetects the end point of the cleaning. As described above, O₂ isgenerated at the same time of the decomposition of SiOF, and the amountof O₂ changes during the cleaning process. That is, the systemcontroller 100 can detect the end point of the cleaning, by monitoringthe amount of oxygen (based on an emission intensity). Note that the endpoint of the cleaning can be detected by any other methods, such as amethod for detecting the pressure inside the chamber, etc.

[0054] Upon the end point of the cleaning, the system controller 100stops applying an RF power to the upper and lower electrodes.Subsequently, the system controller 100 opens the valves VE and VF,supplies the chamber 11 with O₂ and Ar, and starts applying an RF powerto the upper electrode. After this, the system controller 100 stopssupplying the chamber 11 with Ar and applying the RF power to the upperelectrode. The system controller 100 stops supplying the chamber 11 withO₂, and releases the electrostatic chuck. Then, the dummy wafer W iscarried out from the chamber 11, thereby completing the cleaningprocess.

EXAMPLE 1

[0055]FIGS. 2 and 3 show cleaning results achieved after the filmformation which is done using the plasma processing apparatus 10according to the first embodiment of the present invention.

[0056] In this Example 1, during a film formation, a SiOF film is formedto have a thickness of 5 μm on the wafer W, within the distance 50 mmbetween the electrodes. In addition, during a cleaning process, thesystem controller 100 supplies the chamber 11 with NF₃/Ar=500/500(sccm/sccm) at a pressure of 13 Pa, and applies an RF power of 1500W tothe upper electrode (the electrode plate 17).

[0057]FIG. 2 shows the relationship between the cleaning time and theapplied RF power, in the case where the cleaning is performed withapplying the RF power to the upper and lower electrodes using theprocessing apparatus of the first embodiment. As seen from FIG. 2, it isclear that the processing apparatus which applies the RF power to theupper and lower electrodes can achieve the cleaning at a shorter periodof time than the case where the RF power is applied only to the upperelectrode. In the case where RF powers of 300W and 500W are applied tothe lower electrode, the cleaning time is reduced to 76 MIN and 70 MIN,respectively. Accordingly, in the processing apparatus of thisembodiment which performs the cleaning by applying an RF power not onlyto the upper electrode, but also to the lower electrode, a high cleaningrate can be obtained, and hence enabling to perform the cleaning withhigh efficiency.

[0058] In the above-described embodiment, the explanations have beenmade to the pressure inside the processing apparatus according to thefirst embodiment, wherein the pressure inside the chamber 11 is retainedapproximately at a pressure of 13 Pa. However, the present invention isnot limited to the above, and the cleaning may be performed at a higherpressure than the above pressure of 13 Pa.

[0059]FIG. 3 shows the relationship between the cleaning time and thepressure inside the chamber 11. As obvious from FIG. 3, as compared tothe case where the cleaning is done at a pressure of 13 Pa inside thechamber 11, the cleaning time can be reduced in the case where thepressure is increased to a pressure of 50 Pa. Accordingly, a highcleaning rate can be obtained by performing the cleaning at a moderatelevel of a vacuum inside the chamber 11.

Second Embodiment

[0060] A processing apparatus according to the second embodimentincludes a chamber. Inside the chamber, a SiOF film is formed on a waferW using a plasma CVD method, with a process gas containing SiH₄, SiF₄,and O₂. The SiOF film deposited inside the chamber after the filmformation process is removed using a cleaning gas including NF₃. Thecleaning gas is activated outside the chamber so as to be used.

[0061]FIG. 4 shows the structure of the processing apparatus 10according to the second embodiment of the present invention. FIG. 5 is across sectional view of the processing apparatus 10. In FIGS. 4 and 5,the same components are identified by the same reference numerals.

[0062] As shown in FIG. 4, the processing apparatus 10 of the secondembodiment includes a cleaning-gas line L4 provided with an activator27.

[0063] The activator 27 is connected to the cleaning gas source SA andthe carrier gas source SB respectively through the valves VA and VB andalso through mass flow controllers MA and MB. The activator 27 has aplasma generation mechanism. This mechanism activates the gas passingthrough the activator 27, so as to generate plasma of the gas. Ofcleaning gas plasmas, a fluorine radical which is generated from NF₃ isselectively discharged from the activator 27.

[0064] As shown in FIG. 5, the branched cleaning gas lines L4 isconnected to two cleaning gas inlets 28 which are provided at the sidewall of the chamber 11. The two cleaning gas inlets 28 face each otherat the inner wall of the chamber 11. The cleaning gas plasma dischargedfrom the activator 27 is introduced into the chamber 11 through the twocleaning gas inlets 28.

[0065] Operations of the processing apparatus 10 according to the secondembodiment, in the case where the cleaning process is carried out, willnow be explained with reference to FIGS. 4 and 5. The followingoperations will now be described by way of example, and the presentinvention is not limited to the below.

[0066] After the film is formed on a predetermined number of wafers W,the system controller 100 begins the cleaning of the chamber 11.

[0067] The dummy wafer W for cleaning is carried into the chamber 11,and put on the susceptor 12. The dummy wafer W on the susceptor 12 isfixed by the electrostatic chuck. Subsequently, the system controller100 opens the valves VA and VB, and supplies the chamber 11 with NF₃ andAr.

[0068] The cleaning gas is supplied into the chamber 11 at a ratio ofNF₃/Ar=500/500 (sccm/sccm). The pressure inside the chamber 11 duringthe cleaning is retained in a range between 100 Pa and 400 Pa by the APC26.

[0069] After the NF₃ gas and Ar gas are supplied into the chamber 11,the system controller 100 activates the activator 27. The activator 27activates the supplied gas therein to generate plasma of the gas, andthen discharges the plasma (containing mainly fluorine radical) to thechamber 11. The SiOF film remaining and adhered to the inside of thechamber 11 is decomposed to SiF₄, etc. by the cleaning gas mainlycontaining the fluorine radical, so as to be discharged therefrom.Accordingly, the cleaning is thus proceeded, and the SiOF film depositedinside the chamber 11 is removed.

[0070] When the system controller 100 determines that the cleaning hasbeen completed based on the emission intensity of oxygen, it inactivatesthe activator 27. Further, the system controller 100 closes the valvesVA and VB, so as to stop supplying the chamber 11 with the cleaning gas.After this, the system controller 100 opens the valves VE and VF, so asto supply O₂ and Ar into the chamber 11. Subsequently, the systemcontroller 100 releases the electrostatic chuck, and stops supplying O₂and Ar into the chamber 11. After this, the dummy wafer W is carried outfrom the chamber 11, thereby completing the cleaning process.

EXAMPLE 2

[0071]FIG. 6 shows the relationship between the time for cleaning andthe pressure inside the chamber 11, and shows some results of thecleaning done after the film formation, using the processing apparatusaccording to the second embodiment of the present invention. In Example2, during the process for forming the film, a SiOF film is formed tohave a thickness of 5 μm on the wafer W, with the distance of 50 mmbetween the electrodes.

[0072]FIG. 6 shows the results of the cleaning with a variety ofpressure levels. As seen from FIG. 6, as compared to the case where thepressure inside the chamber 11 is in a high vacuum state ofapproximately 0 Pa, a high cleaning rate can be obtained if the pressureis within a range between 100 Pa and 400 Pa. Note also that, in the casewhere the pressure inside the chamber 11 is approximately 200 Pa, themost highest cleaning rate can be obtained. According to the secondembodiment wherein the cleaning is performed at a pressure in a rangebetween 100 Pa and 400 Pa inside the chamber 11, the cleaning candesirably be achieved with high efficiency.

EXAMPLE 3

[0073] In the above-described second embodiment, an RF power may beapplied to the upper electrode. This realizes that the cleaning gas(mainly containing fluorine radical) activated outside the chamber 11can further be activated inside the chamber 11. According to thisstructure, a high cleaning rate can be obtained.

[0074]FIG. 7 shows the relationship between the time for cleaning andthe RF power applied onto the upper electrode, in the case where thecleaning is performed after the SiOF film is formed on the wafer W in athickness of 5 μm. During the cleaning, an RF power of 500W is appliedto the upper electrode, and the pressure inside the chamber 11 is 200Pa.

[0075] As obvious from FIG. 7, if the RF power is applied to the upperelectrode and a remote plasma gas is used for cleaning the chamber 11,the cleaning is achieved at a cleaning time which is shorter than onefifth of the cleaning time in the case where the RF power is not appliedthereto. Accordingly, with applying the RF power to the upper electrodeto activate the cleaning gas in the chamber 11, the cleaning with a highcleaning rate is possible.

[0076] Note that the cleaning may be performed, while the RF power isapplied not only to the upper electrode, but also to the lowerelectrode.

Third Embodiment

[0077] A processing apparatus according to the third embodiment of thepresent invention includes a chamber. In this chamber, a SiOF film isformed on a wafer W using a plasma CVD method, which employs a processgas containing SiH₄, SiF₄ and O₂. The SiOF film remaining and adhered toinside of the chamber 11, after the film formation process, is removedusing a cleaning gas containing NF₃. The cleaning gas is activatedoutside the chamber so as to be used.

[0078] The processing apparatus according to the third embodiment of thepresent invention has the same structure as that of the processingapparatus of the second embodiment shown in FIGS. 4 and 5. FIG. 8 showsthe structure of the process according to the third embodiment. In FIG.8, the same components are identified by the same reference numerals asthose of FIG. 4.

[0079] As shown in FIG. 8, the processing apparatus 10 of thisembodiment includes three cleaning gas inlets 28 at the inner wall ofthe chamber 11. The three cleaning gas inlets 28 are connected to thecleaning gas line L4 respectively. The cleaning gas inlets 28 areprovided approximately at equal intervals. The cleaning gas is suppliedinto the chamber 11 through each of the cleaning gas inlets 28substantially at the same supply pressure.

EXAMPLE 4

[0080]FIG. 9 shows results of film formation processes and cleaningprocesses done by the processing apparatus of the third embodiment. InFIG. 9, comparisons are made to the cleaning results done by theprocessing apparatus of this embodiment. Specifically, the comparisonsare made to one case where the cleaning gas spouts in two ways, and theother case where the cleaning gas spouts into the chamber 11 in threeways.

[0081] In the process for forming the film, a SiOF film is formed in athickness of 5 μm on the wafer W with the distance of 50 mm between theelectrodes. In the cleaning process, the cleaning gas ofNF₃/Ar=1000/1000 (sccm/sccm) is supplied into and through the chamber 11at a pressure of 13 Pa.

[0082] In an experiment, a plurality of chips on each of which a siliconoxide film is formed are provided respectively on a plurality of pointsinside the chamber 11. The thickness of the silicon oxide film of eachof the chips is measured after cleaning. The cleaning rate at each ofthe points in the chamber 11 is calculated, based on a reduction in themeasured thickness of the silicon oxide film.

[0083] The points for measuring the cleaning rate are identified bysymbols of I to V, as illustrated in FIG. 8. For the processingapparatus 10 wherein the cleaning gas spouts in two ways, the cleaningrate is measured at each of the points I to V, as shown in FIG. 10. Thechip at the point I is put on the susceptor 12, and the rest of thechips respectively at the points II to V are put on almost the sameplane as the susceptor 12.

[0084] As seen from FIG. 9, in the case where the cleaning gas issupplied from two points (in two ways), the cleaning rate at the pointII, which is farthest from the cleaning gas inlets 28, is lower than thecleaning rate at any other points I, III, IV, and V. In the thirdembodiment wherein the cleaning gas is supplied from three points (inthree ways), the etching rate at the point II is almost equal to orlarger than the etching rate at any other points I, III, IV, and V. Inconsideration of this, in the processing apparatus 10 of the thirdembodiment thus including the three cleaning gas inlets 28 in thechamber 11, the uniformity of the cleaning rate can be obtained, and thecleaning is performed with high efficiency.

[0085] In the above-described third embodiment, the three cleaning gasinlets 28 are provided at equal intervals on the side wall of thechamber 11. However, the cleaning gas inlets 28 may be provided at anyother intervals. Further, the number of the cleaning gas inlets 28 isnot limited to three, and more than three cleaning gas inlets may beprovided.

Fourth Embodiment

[0086] A processing apparatus according to the fourth embodiment of thepresent invention includes a chamber. In this chamber, a SiOF film isformed on a wafer using a plasma CVD method, which employs a process gascontaining SiH₄, SiF₄, and O₂. The SiOF film remaining in and adhered tothe inside of the chamber after the film formation process is removed bya cleaning gas containing NF₃. The cleaning gas is activated outside thechamber, so as to be used.

[0087] The processing apparatus according to the fourth embodiment ofthe present invention has the same structure as that of the processaccording to the third embodiment shown in FIGS. 5 and 8. In theprocessing apparatus 10 of the fourth embodiment, a lid member 29 shownin FIG. 11 is built on each of the three cleaning gas inlets 28. In thisstructure, the cleaning gas is introduced into the chamber 11 throughthe lid member 29.

[0088] As illustrated in FIG. 11, the lid member 29 is formed in arectangular shape, and has five slit-like openings 30. Those fiveopenings 30 are formed in parallel with each other. The size of the lidmember 29 is approximately the same as the section of each of thecleaning gas inlets 28. The cleaning gas is supplied into the chamber 11through the openings 30. The lid member 29 is made of Al₂O₃, forexample.

[0089] The opening percentage of the lid member 29 is set in a rangefrom 50% to 80%. Note that the opening percentage in this case implies aratio of the entire area of the openings 30 included in the lid member29 to the entire area of the lid member 29, i.e. (Opening (%))=(EntireArea of Openings 30)/(Entire Area of Lid Member 29)×100.

EXAMPLE 5

[0090]FIG. 12 shows results of cleaning experiments done using theprocessing apparatus 10 according to the fourth embodiment of thepresent invention.

[0091] The cleaning experiments are performed in the same manner as thatof the Example 4. In the film formation process, a SiOF film is formedin a thickness of 5 μm on the wafer W, with the distance of 50 mmbetween the electrodes. In the cleaning process, the cleaning gas issupplied at a ratio of NF₃/Ar=1000/1000 (sccm/sccm) and pressure of 13Pa inside the chamber 11.

[0092] The opening percentage of the lid member 29 is set to 62%. Forcomparison, the cleaning experiments are done using a plurality of lidmembers 29 whose opening percentages are 10%, 35%, and 100%,respectively.

[0093] Likewise the Example 4, in the cleaning experiments, chips oneach of which a silicon oxide film is formed are provided at each of thepoints inside the chamber 11. The thickness of the silicon oxide film ismeasured. The cleaning rate at each of the points is obtained bycalculating a reduction in the thickness of the silicon oxide film.

[0094] The points for measuring the cleaning rate are identified bysymbols of I to V, as shown in FIG. 8. Note that the chip at the point Iis put on the susceptor 12, and the rest of the chips at the points IIto V are provided on the same plane as the susceptor 12.

[0095] As seen from FIG. 12, if the opening percentage of the lid member29 is 100%, the cleaning rates respectively at the points I to V widelyvary. If the opening percentage of the lid member 29 is 10% or 35%, thecleaning rates thereat are quite uniform. However, such cleaning rates,in the case of 10% or 35% of the opening percentage, are notsufficiently high. Alternatively, according to the processing apparatusof the fourth embodiment using the lid member 29 whose openingpercentage is 62%, nearly-uniform cleaning rates are highly obtained ateach of the points I to V inside the chamber 11.

[0096] Accordingly, in the processing apparatus 10 of this embodimentusing the lid member 29 whose opening percentage is in a range from 50%to 80%, sufficiently high cleaning rates can be obtained. In addition,the cleaning gas can be supplied into the chamber 11 with uniformity.

[0097] In the fourth embodiment, the openings 30 of the lid member 29are formed in a slit-like shape. However, the shape of the openings 30is not limited to this. For example, the openings 30 may be formed in acircular shape, a polygonal shape, or any other shapes. Further, theplurality of slit-shaped openings 30 may be included in parallel witheach other. In addition, the shape of the lid member 29 is not limitedto the rectangular shape, and the lid member 29 may be formed in acircular shape in conformity with the section of the cleaning gas inlets28.

[0098] In the fourth embodiment, the openings 30 of the lid member 29may be set at a variety of angles, respectively, as shown in FIG. 13. Inthis structure, the cleaning gas can uniformly spout into the chamber11.

[0099]FIG. 13 shows a state wherein the lid member 29 of FIG. 11 isfixed into the cleaning gas inlet 28. Of five openings 30 of the lidmember 29, a central opening 30 a forms a path perpendicular to the mainsurface of the lid member 29. Openings 30 b and 30 c, except the centralopening 30 a, form paths diagonally to the 30 main surface.Specifically, the two openings 30 b adjacent to the central opening 30 aform paths at an angle of 60° with the main surface, whereas the two endopenings 30 c form paths at an angle of 45° therewith.

[0100] In the structure where the lid member 29 includes the openings 30b and 30 c forming the paths diagonally to the main surface, thecleaning gas diagonally spouts from the openings 30 b and 30 c. Hence,the gas spouts evenly from the cleaning gas inlet 28.

EXAMPLE 6

[0101]FIG. 14 shows results of cleaning experiments achieved using theprocessing apparatus 10 according to the fourth embodiment, includingthe lid member 29 of FIG. 13.

[0102] Those cleaning experiments are done in accordance with the samesteps as those of the Example 4. In the film formation process, the SiOFfilm of 5 μm is formed on the wafer W, with the distance of 50 mmbetween the electrodes. In the cleaning process, the cleaning gas flowsinto and through the chamber, at a ratio of NF₃/Ar=1000/1000 (sccm/sccm)and at a pressure of 13 Pa inside the chamber 11.

[0103] The opening percentage of the lid member 29 is set to 35%. Forcomparison, the same cleaning experiment as the experiment of theExample 4 is performed using the lid member 29 including only thevertical openings 30 a of FIG. 15.

[0104] Likewise the Example 4, in the experiments, the chip on which asilicon oxide film is formed is provided on each of the points insidethe chamber 11, and the thickness of the silicon oxide film is measured.The cleaning rate at each of the points is calculated by measuring thereduction in the thickness of the silicon oxide film.

[0105] The points for measuring the cleaning rate are identified by thesymbols of I to V shown in FIG. 8. The chip at the point I is put on thesusceptor 12, and the rest of the chips at the respective points II to Vare provided almost on the same plane as the susceptor 12.

[0106] As obvious from FIG. 14, in the case where the lid member 29including only the vertical openings 30 a is used, the cleaning rate isthe lowest at the point III, and the cleaning rate widely vary at eachpoints I to V. In the case where the lid member 29 including thediagonal openings 30 b and 30 c is used, the cleaning rates areapproximately the same at the respective points II to V, i.e. except atthe point I (on the susceptor 12). Accordingly, with the utilization ofthe chamber 29 including the openings 30 b and 30 c forming the paths atpredetermined angles (e.g. 45°, 60°), the cleaning gas is supplied indifferent directions into the chamber 11, thereby enabling to evenlyclean the inside of the chamber 11.

[0107] In the above examples, the angles of the paths from the diagonalopenings 30 b and 30 c are not limited to 45° and 60°, and may be 70°,30°, etc. In addition, in accordance with the number of the openings 30,the angles of the paths from the openings 30 may be changed. Forexample, if the number of the openings 30 is seven, the seven openings30 may form paths having respectively an angle of 90°, 60°, 45°, and30°, sequentially from the central one to both end openings.

Fifth Embodiment

[0108] A processing apparatus according to the fifth embodiment of thepresent invention includes a chamber. In this chamber, a SiOF film is ona wafer W using a plasma CVD method, which employs a process gascontaining SiH₄, SiF₄ and O₂. The SiOF film remaining and adhered to theinside of the chamber 11 is removed using a cleaning gas containing NF₃.This cleaning gas is activated outside the chamber 11 so as to be used.

[0109] The processing apparatus according to the fifth embodiment of thepresent invention has the same structure as that of the processingapparatus of the second embodiment which is shown in FIG. 4. In theprocessing apparatus according to the fifth embodiment, the chamber 11is connected to the process gas line L1, the exhaust line L3, and thecleaning gas line L4.

[0110]FIG. 16 shows the processing apparatus 10 according to the fifthembodiment, in section. In FIG. 16, the same components are identifiedby the same reference numerals as those of FIG. 5. For the sake ofsimplicity, the gas lines and RF power sources are not illustrated inFIG. 16.

[0111] In the processing apparatus 10 shown in FIG. 16, chiller paths 31are embedded in the electrode supporter 18 and the side wall of chamber11. A chiller flows through the chiller paths 31, thereby the internalsurface of the chamber 11, especially the electrode plate 17 supportedby the electrode supporter 18 and the wall of the chamber 11, areretained at a predetermined temperature. In the cleaning process, thesystem controller 100 controls the flow system of the chiller so as toadjust the temperature of the chamber 11. In this specification, theterm, chiller, implies a fluid material for maintaining the temperatureof an object, but not for simply cooling (chilling) an object. Theinside of the chamber 11 which is in a vacuum state is thus essentiallyretained at a very low temperature, so that the electrode plate 17, etc.is substantially heated up by the chiller.

[0112] The electrode plate 17 has a plurality of holes 17 a forintroducing the process gas into the chamber 11. In this structure, theelectrode plate 17 is one component onto which the film is most likelyto be adhered, and hence is one component which should firstly becleaned among of the chamber member. Because of the structure that theelectrode plate 17 includes the plurality of holes 17 a, the electrodeplate 17 can not easily be cleaned. By heating the electrode plate 17using the chiller, the cleaning rate of the electrode plate 17 canpartially be enhanced.

EXAMPLE 7

[0113] The cleaning process is carried out on the following conditions,using the processing apparatus 10 of this embodiment which includes thelid member 29. In the film formation process, a SiOF film is formed in athickness of 5 μm on a wafer W with the distance of 50 mm between theelectrodes. In the cleaning process, the cleaning gas at a ration ofNF₃/Ar=1000/1000 (sccm/sccm) flows at a pressure of 13 Pa into thechamber 11. The temperature of the chiller flowing into the electrodesupporter 18 and wall of the chamber 11 is set to 100° C. To obtain theexperimental outcome, the chip on which the silicon oxide film is formedis provided on the electrode plate 17, and a reduction in the thicknessof the silicon oxide film is measured.

[0114]FIG. 17 shows such experimental results. As seen from FIG. 17, ascompared to the case where the electrode plate 17 is not heated, a highcleaning rate at the electrode plate 17 can be obtained in the casewhere the electrode plate 17 is heated. According to the processingapparatus of the fifth embodiment, wherein the electrode plate 17 isheated, the cleaning rate can be enhanced at the electrode plate 17which is difficult to sufficiently be cleaned, thus enabling to evenlyperform the cleaning of the chamber 11. Further, by heating the wall ofthe chamber 11, the cleaning rate can highly be obtained throughout thechamber 11.

[0115] In the fifth embodiment, the walls of the electrode plate 17 andchamber 11 are heated by the chiller. However, the wall may be heatedusing any other methods.

[0116] For example, as shown in FIG. 18, instead of the chiller paths31, a heater 32, such as a resistor, etc. may be included in the chamber11.

[0117] As shown in FIG. 19, the walls of the electrode plate 17 andchamber 11 may be heated by a lamp 33, such as a halogen lamp, etc. Inthis case, a window 34 may be prepared on the side surface of thechamber 11, so that the electrode plate 17, etc. is heated byirradiating light thereto from the lamp 33 through the window 34.

[0118]FIG. 17 also shows results of cleaning experiments, respectivelyin the cases where the electrode plate 17 is heated by the heater 32shown in FIG. 18 and heated by the lamp 33 shown in FIG. 19, in additionto the cases where the electrode plate 17 is not heated and is heated bythe chiller. The heater 32 and the lamp 33 are set at 100° C.

[0119] As seen from FIG. 17, the electrode plate 17 is heated by theheater 32 or the lamp 33, to obtain a high cleaning rate at theelectrode plate 17. Accordingly, the electrode plate 17 is heated,thereby enhancing the cleaning rate at the electrode plate 17 which cannot sufficiently be cleaned.

[0120] In the fifth embodiment of the present invention, the temperatureof the heater 32 or lamp 33 is set at 100° C. However, the temperatureis not limited to 100° C., as long as the cleaning inside the chamber 11can evenly be achieved.

[0121] In the above-described first to fifth embodiments, the SiOF filmis formed on the wafer W, and the cleaning of the chamber 11 is doneusing an NF₃ gas, in the parallel-plate-type plasma processing apparatus10. However, the film to be formed is not limited to the SiOF film, anda silicon-containing film, such as SiO₂, SiC, SiN, SiCN, SiCH, SiOCH,etc. may be formed. The cleaning gas may include, not only the NF₃ gas,but a fluorine-containing gas, such as CF₄, C₂F₆, SF₆, etc., or achlorine-containing gas, such as Cl₂, BCl₄, etc. The present inventionmay also be applied to a processing apparatus wherein LCD (LiquidCrystal Display) devices are processed.

[0122] In the second to fifth embodiments, the cleaning gas is activatedso as to generate plasma of the cleaning gas, especially containingradicals. However, by activating the cleaning gas, the active species,other than the radicals, may be employed, so as to perform the cleaningof the chamber.

[0123] The present invention according to the second to fifthembodiments is applicable, not only to the parallel-plate-type plasmaprocessing apparatus, but any other type of plasma processing apparatus,such as an ECR-type processing apparatus, an ICP-type processingapparatus, a helicon-type processing apparatus, a micro-wave-typeprocessing apparatus, etc. In addition, the present invention isapplicable not only to the plasma processing apparatus, but any otherprocessing apparatus, such an etching apparatus, a sputtering apparatus,a heat processing apparatus, etc.

Industrial Applicability

[0124] The present invention mentioned above is useful for manufacturingsemiconductor products.

[0125] This application is based on Japanese Patent Application No.2000-239426 filed on Aug. 8, 2000 and including specification, claims,drawings and summary. The disclosure of the above Japanese PatentApplication is incorporated herein by reference in its entirety.

1. A processing apparatus (10) comprising: a chamber (11); a gas source(SA) for supplying a gas for cleaning inside of said chamber (11); a gasline (L1) for introducing the gas supplied from said gas source (SA)into said chamber (11); an activator (12) which is prepared in said gasline (L1) and activates the gas supplied from said gas source (SA); andat least three gas inlets (28) which are provided at a side wall of saidchamber (11) and connected to said gas line (L1).
 2. The processingapparatus (10) according to claim 1, wherein said at least three gasinlets (28) are provided at equal intervals.
 3. The processing apparatus(10) according to claim 1, wherein said processing apparatus (10)includes a plasma generation mechanism for providing a target objectwith plasma processing in said chamber (11).
 4. The processing apparatus(10) according to claim 1, wherein said activator (12) generates plasmaof the gas.
 5. A processing apparatus (10) comprising: a chamber (11); agas source (SA) for supplying a gas for cleaning inside of said chamber(11); a gas line (L1) for introducing the gas supplied from said gassource (SA) into said chamber (11); an activator (12) which is preparedin said gas line (L1) and activates the gas supplied from said gassource (SA); and a gas inlet (28) which is provided on a surface of saidchamber (11) and connected to said gas line (L1), and wherein said gasinlet (28) is covered with a lid member (29) including at least oneopening (30) having an area in a range between 50% and 80% of an area ofa main surface of the lid member (29).
 6. The processing apparatus (10)according to claim 5, wherein said processing apparatus (10) includes aplasma generation mechanism for providing a target object with plasmaprocessing in said chamber (11).
 7. The processing apparatus (10)according to claim 5, wherein said activator (12) generates plasma ofthe gas.
 8. A processing apparatus (10) comprising: a chamber (11); agas source (SA) for supplying a gas for cleaning inside of said chamber(11); a gas line (L1) for introducing the gas supplied from said gassource (SA) into said chamber (11); an activator (12) which is preparedin said gas line (L1) and activates the gas supplied from said gassource (SA); and a gas inlet (28) which is provided on a surface of saidchamber (11) and connected to said gas line (L1), wherein said gas inlet(28) is covered with a lid member (29) including at least one opening(30) which is provided diagonally with respect to a thickness directionof the lid member (29).
 9. The processing apparatus (10) according toclaim 8, wherein said processing apparatus (10) includes a plasmageneration mechanism for providing a target object with plasmaprocessing in said chamber (11).
 10. The processing apparatus (10)according to claim 8, wherein said activator (12) generates plasma ofthe gas.
 11. A processing apparatus (10) comprising: a chamber (11); agas source (SA) for supplying a gas for cleaning inside of said chamber(11); a gas line (L1) for introducing the gas supplied from said gassource (SA) into said chamber (11); an activator (12) which is preparedin said gas line (L1) and activates the gas supplied from said gassource (SA); and a heat mechanism for heating the internal surface ofsaid chamber (11).
 12. The processing apparatus (10) according to claim11, wherein said heat mechanism includes a path (31) for chillerembedded in said chamber (11).
 13. The processing apparatus (10)according to claim 11, wherein said heat mechanism includes a heater(32) which is embedded in said chamber (11).
 14. The processingapparatus (10) according to claim 11, wherein: said chamber (11)includes a window (34); and said heat mechanism is provided outside saidchamber (11) and includes a lamp (33) for irradiating light to theinternal surface of the chamber (11) through the window (34).
 15. Theprocessing apparatus (10) according to claim 11, wherein said processingapparatus (10) includes a plasma generation mechanism for providing atarget object with plasma processing in said chamber (11).
 16. Theprocessing apparatus (10) according to claim 11, wherein said activator(12) generates plasma of the gas.
 17. A method for cleaning a processingapparatus (10) including two electrodes in a chamber (11), said methodcomprising the steps of: introducing a gas for cleaning into saidchamber (11); and applying an RF power to each of the two electrodes(12, 17), thereby activating the gas for cleaning.
 18. The methodaccording to claim 17, wherein the gas for cleaning is activated togenerate plasma thereof.
 19. A method for cleaning a processingapparatus (10) including two electrodes (12, 17) in a chamber (11), saidmethod comprising the steps of: activating a gas for cleaning outsidesaid chamber (11); introducing the activated gas into said chamber (11);and applying an RF power to at least one of the two electrodes (12, 17),thereby activating the gas for cleaning.
 20. The method according toclaim 19, wherein the gas for cleaning is activated to generate plasmathereof.
 21. A method for cleaning a processing apparatus (10) includinga chamber (11), said method comprising the steps of: activating a gasfor cleaning outside said chamber (11); and introducing the activatedgas into the chamber (11) in at least three ways.
 22. The methodaccording to claim 21, wherein said processing apparatus (10) provides atarget object with plasma processing in the chamber (11).
 23. The methodaccording to claim 21, wherein the gas for cleaning is activated togenerate plasma thereof.
 24. A method for cleaning a processingapparatus (10) including a chamber (11), said method comprising thesteps of: activating a gas outside the chamber (11); and introducing theactivated gas into the chamber (11) in various directions.
 25. Themethod according to claim 24, wherein said processing apparatus (10)provides a target object with plasma processing in the chamber (11). 26.The method according to claim 24, wherein the gas for cleaning isactivated to generate plasma thereof.
 27. A method for cleaning aprocessing apparatus (10) including a chamber (11), said methodcomprising the steps of: activating a gas for cleaning outside thechamber (11); introducing the gas into the chamber (11); and retainingpressure in the chamber (11) in a range between 100 Pa and 400 Pa. 28.The method according to claim 27, wherein said processing apparatus (10)provides a target object with plasma processing in the chamber (11). 29.The method according to claim 27, wherein the gas for cleaning isactivated to generate plasma thereof.
 30. A method for cleaning aprocessing apparatus (10) including a chamber (11), said methodcomprising the steps of: activating a gas for cleaning outside thechamber (11); introducing the gas into the chamber (11); and heating aninner surface of the chamber (11).
 31. The method according to claim 30,wherein said processing apparatus (10) provides a target object withplasma processing in the chamber (11).
 32. The method according to claim30, wherein the gas for cleaning is activated to generate plasmathereof.